MicroRNAs (miRNAs) are emerging materials as ideal biomarkers for noninvasive cancer detection in the early phase. In this article, a simple and label-free electrochemical miRNA biosensor was developed. A single-stranded DNA (ss-DNA) probes were successfully mapped to f-MWCNT and hybridized with the target miR-141 sequence. The optimum peak points of the obtained hybridization were determined using Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV) methods. Significant peaks were observed in the results, depending on miR-141 at different concentrations. The linear relationship (ν) between redox peak currents (Ip) and scanning rate indicated that electron transfer (ET) between miR-141 and the electrode surface was accomplished successfully. In DPV measurements, miR-141 was measured with a low detection limit (LOD) in the 1.3–12 nM concentration range, and the LOD and limit of quantification (LOQ) results were found to be 3 and 9.1 pM, respectively. Besides, selectivity test was investigated for the biosensor using different target analytes and a significant difference in value was observed between the peak currents of miR-141, and other target molecules. This developed strategy has been found to detect miR-141 sensitively, selectively and without tags, and its integration into mobile devices has been successfully carried out.

Modified screen-printed electrochemical biosensor design compatible with mobile phones for detection of miR-141 used to pancreatic cancer biomarker
    Abstract
    1 Introduction
    2 Material and method
        2.1 Chemicals
        2.2 Devices used in the study
        2.3 Electrochemical miRNA biosensor fabrication
    3 Results and discussion
        3.1 Material characterization for f-MWCNT
        3.2 Electrochemical measurements of modified electrodes
        3.3 Performance of biosensor designed for quantitative analysis of miRNA-141
        3.4 Selectivity
    4 Conclusion
    Anchor 14
    Acknowledgements 
    References

• Muhammed Bekmezci(SRG Incorporated Company, Kutahya Design Technopole, Calca OSB Neighbourhood, 431000 Kütahya, Turkey)
• Ramazan Bayat(SRG Incorporated Company, Kutahya Design Technopole, Calca OSB Neighbourhood, 431000 Kütahya, Turkey)
• Merve Akin(SRG Incorporated Company, Kutahya Design Technopole, Calca OSB Neighbourhood, 431000 Kütahya, Turkey)
• Zeynep Kazel Coguplugil(SRG Incorporated Company, Kutahya Design Technopole, Calca OSB Neighbourhood, 431000 Kütahya, Turkey)
• Fatih Sen(SRG Incorporated Company, Kutahya Design Technopole, Calca OSB Neighbourhood, 431000 Kütahya, Turkey)